Abstract: Objective To explore whether Mycobacterium tuberculosis (Mtb) regulates the expression of IFNAR gene and its role in the patients with tuberculosis (TB). Methods The cases were selected from Shenzhen Third People’s Hospital during January to May 2013，involving sputum smear-positive TB patients（n=15），the persons with latent tuberculosis infection (LTBI) (n=15) and healthy controls (HC) (n=15). CD14⁺ monocytes were isolated from peripheral blood mononuclear cells (PBMCs) and differentiated into human macrophages under macrophage colony stimulatory factor (M-CSF) stimulation，then expression of IFNAR1 and IFNAR2 genes was determined with qPCR assay after infection with Mtb H37Ra or H37Rv strains. All data was dealt with GraphPad 4.0 software. The homogeneity test of variances was used to judge whether multiple measurement data were in Gaussian distribution，if so，the data was shown as x±s and analysis of variance（ANOVA）was used to compare multiple comparison to calculate q value. Enumeration data was compared with R×C Chi-square test. It was considered as signifi-cant difference with P<0.05. Results IFNAR1 gene expression in the macrophages infected by Mtb H37Rv decreased significantly compared to the blank control (5.95±0.41 vs 7.53±0.41，q=4.15，P<0.05). IFNAR1 gene expression in the macrophages infected by Mtb H37Ra（6.54±0.33） had not significant difference with the blank control （7.53±0.41）and H37Rv infection（5.95±0.41）（q=2.56 and 1.57，P>0.05）. IFNAR2 gene expression had not significant difference in the macrophages infected by Mtb H37Rv （8.81±0.85）or H37Ra （8.84±0.80）（q=0.02，P>0.05）, but they were significantly lower compared to the blank control（12.67±1.15）（q=4.10 and 4.13，P<0.05）. Furthermore， IFNAR1 gene expression had no significant difference among different groups（TB 5.39±0.64；LTBI 6.59±0.86；HC 7.08±1.10，P>0.05），and IFNAR2 gene expression was lower in TB than that in HC（5.96±0.58 vs 10.01±1.58，q=3.67，P<0.05）. Conclusion Mycobacterium tuberculosis could induce down-regulation of IFNAR gene expression in the macrophages, which was not associated with virulence of Mtb. IFNAR2 gene expression was lower in TB and could be considered as a new diagnosis marker.

Key words: Tuberculosis, Mycobacterium tuberculosis, Receptor, interferon alpha-beta, Gene expression regulation, Macrophages